Method of making printing rolls



April 18, 1944. J. .1. ORMOND METHOD (5F MAKING PRINTING ROLLS Filed April 25, 1941 Patented Apr. 18, 1944 METHOD OF MAKING PRINTING ROLLS John J. Ormond, Boston, Mass., assignor of twothirds to Joseph D. Ramsey, Boston, Mass.

Application April 23, 1941, Serial No. 389,951

3 Claims. (01. 95-5.?)

This invention relates to methods of makin printing members, and more especially to methods of making intaglio printing rolls of the type used in textile printing.

In making textile printing rolls, it is necessary to form intaglio printing portions of design subject matter repeated around the surface of a printing roll. Very careful preparation .of the printing portions is necessary in order to prevent a break or line, along points where one of the designs joins a, succeeding design, from appearing in a continuous web of cloth over which the roll is passed in carrying out the textile printing operation. This problem is made more diillcult by reason of the fact that several different colors are usually desired to be utilized in juxtaposed relation to one. another. The procedures now resorted to are slow, in some cases inaccurate, and require skilled labor, which greatly increases the cost of printed textiles.

A chief object of the present invention is to improve methods of making printing members and to devise a method of preparing a textile printing roll which includes procedures for forming continuousdesign printing portions around a roll surface without having any break or line occurring alongthose points at which the design portions are repeated. Another object of the invention is to provde a method of making a. textile printing roll which may be quickly carried out, which requires less skilled labor, which is very.accurate and which is adapted to effect I substantial savings. Another object of the in-- vention is to provide an improved photographic element particularly adapted to making textile printing rolls, and to present a method of making printing rolls by the use of photographic materials. Still another object of theinvention is to devise improved methods of etching rolls.

Fig. 1 is a fragmentary plan view,of a strip employed in carrying out the method of the invention;

Fig. 2 is a fragmentary elevational view illustrating application of the strip to a printing roll;

Fig. 3 is a fragmentary elevational view illustrating a printing roll finished in accordance with the method of the invention; and

Fig. 4 is a fragmentary elevational view illustrating a modified method of the invention.

The nature of the invention, and its objects, will be further understood from the following description and appended claims.

In textile printing, it is customary to provide copper printing rolls which have recessed printing surfaces, or intaglio printing portions, particularly adapted to holding large amounts of dyes or other materials applied on textiles. The roll is etched by some suitable acid such as iron perchloride, and etching is controlled to take placev in selected areas on a roll surface by first applying acid resisting materials, such as asphaltum or other suitable substances. The acid resist outlines are customarily drawn in by hand or by the use of devices such as pantogra'ph machines. 1

According to the invention, I form a series of design printing portions which are repeated around a roll surface along a helical path which extends from one end of the roll to its opposite end in a plane wrapped around the roll. This procedure of repeating design printing portions along a helical path on the surface of a roll may be carried out in several ways, and may make use of various instrumentalities.

In one method of the invention, a copper roll of suitable diameter and length is covered with a light-sensitive acid-resisting material as asphaltum. I then provide a strip of translucent material such as a translucent paper, and on the paper I print with an opaque ink, such as lithographic printing ink, portions of subject matter or designs desired to be etched into the surface of the roll. The printed subject matter is arranged on the strip in an angular position with respect to its sides, so that it will occur on the surface of the roll in a squarely disposed manner with respect to the ends of the roll after the strip is wound along a helical path around the roll with its edges in abutting relation. The strip isof a length corresponding to the length of strip necessary to completely cover the surface of the roll when wound diagonally therearound, and each portion of the translucent strip carries that part of the design subject matter which it would receive if the design were printed on the strip while wound around the roll.

The strip and roll are exposed to strong light such as photographic light, to expose uncovered parts of asphaltum. Thereafter the strip is removed andv the ink material, together with the unexposed asphaltum, are washed away with a material such as turpentine, which cleanly removes the unexposed portions of the asphaltum in accordance with the design portions covered by the ink on the strip. The roll is then etched by placing it in a bath of acid as iron perchloride for a suitable length of time. If desired, various screens, ground lines and the like may be incorporated with the inked strip to provide inkretentive grounds of the type usually employed in textile printing rolls.

It is contemplated that the inkedstrip be formed in various ways. It may be cut with irregular edges which are particularly shaped to avoid breaking designs all the way around a roll. The subject matter may be divided up into squares on a master sheet and then applied on the strip so that a single design portion may occur within the width of the strip or may extend across several widths of the strip. The designs may be drawn on the strip'or printed thereon either in a flat state or while wound around a roll of a similar diameter to the diameter of a roll to be etched. Various other methods of making the strip may also be resorted to as will appear more fully hereinafter.

Referring more in detail to the drawing, numeral I indicates a strip of translucent material such as translucent paper. A series of designs 2 is printed on the strip l as illustrated in Fig. l, with the designs being arranged to occur angularly with respect to the parallel edges 3 of the strip.

Fig. 2 illustrates a textile roll 4 which is to be engraved. The outer periphery of the roll is covered with a coating 5 of a light-sensitive acidresisting material such as asphaltum. Around this asphaltum surface is wound a strip l along a. helical path, as illustrated in Fig. 2. By properly arranging the strip I, a substantially vertical position of the designs 2 with reference to the axis of the roll 4 is achieved, while edges of the strip are brought into abutting relation throughout its position around the roll surface. The roll and strip assembly is exposed to light which hardens the asphaltum 5 at all points except those covered by the designs 2 on the strip, which are formed of an opaque ink. When sufilcient hardening has been allowed totake place, the strip is removed and the unhardened areas of the asphaltum which occurred directly below the opaque ink designs 2 are dissolved away by the use of a suitable solvent of the conventional type, thus leaving bare the surface of the roll 6% at these points. The roll is thereafter immersed in lath of etching reagent of some suitable charthe etched designs 3 on the surthe roll which are adapted to receive inn and print in accordance with the conven tional. intag'ilo methods of roll printing.

1 4 strates s. modified type of strip E hating i 6512. 21? wavy edges it, which are adapted re e a means going around designs to ously aroond the surface of having a break occurring in the he method of utilizing a strip of ircharacter is to apply a strip to a be etched, and lightly mark out he of the strip the desired designs rich are to be printed thereon. With the designs thus roughly marked out, t .e edges of the strio can be out along irregular paths which will avo'd intersecting the designs. The strip may hen be removc-xiv and inked with an opaque ink uilizeci in the manner already described. The method of the invention includes specific methods of etching which may be desired to be resorted to in carrying out the above noted process. C ne etching method consists in coating a roll surface with a light-sensitive coating material. such as a mixture of albumin, ammonium bichromate, and an acid-resistant ingredient. The coating is exposed and developed in. the usual manner to provide exposed roll surfaces. The

roll is then subjected to a very short immersion in an acid bath, such as iron perchloride, to carry out a first "bite" which is relatively shallow in relation to the actual bite or depth which is desired to be obtained in the finished printing portions of the roll.

The first bite cuts very lightly into the roll surface. Immediately thereafter an acid-resisting material such as asphaltum, which is much more strongly acid-resisting than the albumin, is applied by means of the diagonally wound strip, for example, to those parts of the roll surface which are covered with the first acid-resisting material. None of the asphaltum is transferred to the roll surface which has been lightly etched. The result is to reinforce the first acid-resisting material in which the printing portions have been defined with a stronger acid-resisting material. Thereafter stronger bites with the acid may be carried out to obtain a proper depth of etch. This procedure combines the use of quick exposure and development from a coating of the albumin type, with the strongly acid-resisting character of a resist such as asphaltum.

Another etching procedure which may be desired to be resorted to, particularly in connection with metals of a harder character than copper. as for instance brass, steel and others, consists in coating a roll with light-sensitive asphaltum, and then printing an outline of subject matter desired to be etched, on the asphaltum coating,

making use of a printing ink which is highlyv absorptive of metal powders. For example, an ink made up oflinseed oil and a pigment such as red lead is suitable and will readily absorb relatlvely large amounts of metallic powders such as aluminum or bronze. A tacky ink image of this character is sprinkled over with a powder such as aluminum or bronze. The powder is absorbed in the ink-covered areas, but may be readily blown away from the relatively slick surface of the dry asphaltum coating at all other points.

The metallic powder renders the ink image highly opaque and the asphaltum coating may then be exposed to strong light to harden all portions of the asphaltum not covered by the opaque ink. The opaque ink and unhardened portions of the asphaltum may then be dissolved away by the use of a suitable solvent such as turpentine, which exposes the metal surface of the roll in accordance with subject matter desired to be etched thereon. The roll is then immere-ed in a bath of a strong acid such as nitric or murlatic acid, to obtain desired etching.

The coating of asphaltum first applied on the roll is of sufiicient strength to resist penetration by these strong acids. However, the procedure outlined allows this relatively strong acidresisting asphaltum to be removed along sharply defined lines in accordance with a. design desired; to be reproduced, and this result is obtained quickly and eiliciently.

The procedure of forming repeated design printing portions along: 9, helical path which passes through 9. plane wrapped around; a. cylinoler may be repateol with respect to other rolls which are to carry additional colors making up a multicolor design. It is pointed out that the use of an inked strip of tran lucent material, diagonally wound around a roll to e etched, illustrates one method of forming repeated design printing portions, various other ways of using a diagonally wound strip may he resorted to. For example, 2, strip of flexible material, which need not necessarily be translucent, is inked with desired design portions, utilizing an ink of a character which is opaque or can be rendered so by some procedure such as one of those already noted. The strip is wound around a roll surface coated with light-sensitive asphaltum as described, and thereafter the strip is removed. The ink is offset to the asphaltum and treated to render it opaque. The coating is exposed to light and developed. Thereafter etching is carried out to obtain the desired printing portions.

In printing subject matter on the strip by mechanical means, various kinds of printing plates may be resorted to, as lithographic printing members, relief printing members, and intaglio printing members. It is also intended that the formation of printing portions, along a helical path, on a roll surface to avoid lines of other indications of lapp n or breaking on the roll surface, may be carried out with respect to other kinds ious changes and modifications may be resorted to, in keeping with the spirit oi the invention as defined by the appended claims.

I claim: i. That improvement in methods etching printing rolls which comprisesproviding a lighting, and etching.

sensitive coating on a printing roll, then transi'erring opaque designs to the suriace oi the lightsensitive coating by means of a diagonally wound strip on which the opaque material is first applied, said opaque material occurring angularly with respect to the paralleLed ge of'the strip 5 whereby the design, when applied on a lightsensitive coating, occurs squarely with respect to the axis of the printing roll, exposing the roll to light to harden parts of the light-sensitive coating on the printing roll, removing unhardened parts of the light-sensitive coating. and etching.

2. That improvement in etching printing rolls which comprises providing a light-sensitive coating on a printing roll, preparing a translucent strip of material with designs of opaque material, said designs occurring obliquely with respect to edges oi the strip and in spaced relation thereto. arranging the strip in a diagonally wound manner about the light-sensitive coating so that the vertical axis of each of the designs occurs perpendicularly with respect to the axis oi the roll. of printing rolls than the intaglio printing rolls used for textile printing, with which this invenexposing to light to harden portions of the lightsensitive coating. removing unhardened portions of the light-sensitive coating, and etching.

3. That improvement in methods of making printing'rolls which comprises providing a lightsensitive coating on a printing roll, arranging a diagonally wound strip about the surface of the light-sensitive coating, said strip being of a translucent character and including a series of opaque designs anguiarly arranged in spaced relation between the edges of the strip, said edges of the strip being or irregular formation. exposing to light to harden portions of the light-sensitive coating, removing unexposed portions oi the coat- JOHN J. ORMOND. 

